Resistant Hypertension and Renal Denervation Where to Now?

Summary Treatment resistant hypertension (TRH) is a major clinical problem with limited treatment options. Renal denervation (RDN) arose as a safe and very effective treatment for TRH with early studies showing dramatic blood pressure reductions however subsequent studies have not shown such a benefit. This review discusses the pathophysiology of TRH and the results of the published studies in RDN for TRH. The initial symplicity (1 and 2) studies using the Ardian RDN catheter showed that office blood pressures were significantly reduced 6 months following the procedure. However these initial studies were limited by a lack of a true control group and inadequate blinding. Subsequent studies (symplicity 3 and simplicity flex) included patients with elevated blood pressures on 24 hr ambulatory blood pressure monitor as well as office measurements. Furthermore, both included a sham arm where patients were randomized to undergo renal angiography alone or RDN, patients were blinded to whether they were in the treatment or sham arm. These more recent studies showed that in both the control and treatment group while there was a significant BP reduction from baseline there was no difference between the groups. Thus RDN appears to have no benefit in blood pressure reduction in those with TRH. RDN currently should only be used in patients with TRH as part of a properly designed clinical study. Pre clinical data suggests that renal sympathetic overactivity is an issue in younger hypertensive patients and this may be the group in which future studies using RDN should focus.